Process of making diazo compounds.



NTTn STATss Patented July 4, 1905.

TRAUGOT'L SANDMEYER, OF BASEL, SWVlTZERLA-ND, ASSIGNOR TO ANILINE COLOR AND EXTRACT \VORKS,.FORMERLY JOHN R. GEIGY, OF BASEL,

SlVITZERLANl).

PROCESS OF MAKING DIAZO COMPOUNDS.

SPECIFICATION forming part of Letters Patent No. 793,743, dated July 4, 1905.

Application filed September 30, 1904. Serial No. 226,619. (Specimens) To all whom, it 777/67] concern:

Be it known that I, TRAUGOTT SANDMEYER, of Basel, Switzerland, have invented new and useful Improvements in Processes of Making 5 Diazo Compounds, of which the following is a specification.

This invention is based upon the discovery that sulfo-acids of the l-amido-Q-naphthol can be transformed under certain conditions into the corresponding diazo compounds or sulfoacids of the naphthalene-1-2diazo oxid, (Bamberger, Br)". 1). 1). (17/1022. (I'm, XXVII, 683,) which new diazo compounds are obtained in pure and dry state in the form of free sul- I fonic acids or their salts. Hitherto by diazotizing the aforesaid sulfonic acids of the 1 -amido2naphthol in the usual mannernamely. in the presence of free mineral acidsthe nitrous acid reacts chiefly as oxidizing 20 agent transforming the amidonapthol sulfonie acids mostly into naphthochinone sulfonic acids. Now I have made the surprising observation that without an addition of a mineral acid, but only by mixture of a l-amido-Q-naph- 5 tholmono or polysulfonic acid or its acid salt with a solution of sodium nitrite, an easy and complete diazotation takes place if a proportionally small quantity of a neutral copper salt,

has been first added to the sulfonic acid or to the sodium nitrite. In a limited measure the same catalytic effects are also shown byother metallic salts, especially iron salts.

The following examples are given to illustrate the method of carrying out the invention:

4 with the cold concentrated solution of one kilo of copper sulfate, after which immediately a concentrated solution of 3.5 kilos of sodium nitrite is slowly added while stirring. Oorresponding with the addition of the nitrite the a clear orange-yellow solution, which is filtered off from any eventually undiazotized particles of the amide acid. After addition of concentrated hydrochloric acid the filtrate changes into a thick paste of the precipitated 5o diazo compound, which is liltered off, washed with diluted hydrochloric acid, pressed, and dried.

l-diazo-Q-naphthol-4:- sulfonic acid forms a grey yellowish crystalline powder, soluble witha pale yellow color in pure water, from which solution however it is for the greatest part precipitated in the form of yellowish line needles upon addition of hydrochloric acid. \Vith resorcin in alkaline solution it combines immediately to a black-violet dyestuff.

Erma/pic 2] "1 oil action of I-(Ziceo-Q-avrtg) 71 t/ml- 6 "816]; fan/11c (mid 0r nap/whale?)c-1-2-(ZM20- omirZ-(i-saifbmfc ac irl 'lwelve kilos of 1- amido-2-naphthol-(i-sulfonic acid in one hundred liters of water mixed with a solution of eight hundred grams of copper chlorid are diazotized while cooled with ice by gradual addition of 3.5 kilos of sodium nitrite. The filtered diazo solution is slightly acidulated 7 with pure hydrochloric acid, then mixed with a solution of barium chlorid. after which the barium salt of the 1 diazo 2 napl1thol-6-sulfonic acid separates as a heavy golden-yellow precipitate, which is filtered off, washed, and 75 dried.

Ema mph 3-Pr0r7rwtvi0n of 1-(Zi/t20-Q-1M flizf/iol fl-d-ci isulfow/ic acid 01' w rap/whale); 0-] 4211 c.20 ormlrl 3 6 (Mail/[fence cciich eventecn kilos of the acid sodium salt of the l-amido-Q- 8O naphthol-3-6-disulfonic acid in one h undred liters of Water arediazotized after addition of one kilo of copper sulfate in the above-described manner. The acid sodium salt of the l-diazo- 2 naphthol 3 6 disulfonic acid is separated 5 from the acidulated yellow solution by means of common salt in the form of an amorphous yellow precipitate.

Having now described my invention, what 45 diazotation takes place, and it results finallyl I claim is o The herein-described process for the proto this specification in the presence of tWo subdudction of sulfolnic acids of the nlaph tha1ene-l1 scribing Witnesses. 2- iazo oXid, W liCh consists in c iazotizing t 1e r r v sulfonic acids of the l-amido-Q-naphthol With DRAUGOlr SANDMEYER' 5 sodium nitrite in the presence of a neutral Witnesses:

copper salt, substantially as set forth. ALBERT GWIETER,

In testimony whereof I have signed my name GEO. GIFFORD. 

